Carbon Arc Lights Used at Airports
(Carbon arc lights that illuminated the skies and airfields in the 1920's)
From the library
Larry Brian Radka
(Editor of The Electric Mirror on the Pharos Lighthouse and Other Ancient Lighting)
Carbon arc searchlights in the Mount Valerien aerial lighthouse and those
worth one billion candlepower on an African mountain near Dijon
Above we see two powerful types of French carbon arc airport lights. Each of the two-meter metallic mirrors of the aerial beacons on the left reflected a brilliant 800,000,000 candlepower beam of light into the skies around Paris in 1921. These airport arc lights each brandished a horizontal set of carbons drawing 300 amperes at 90 volts. When the atmosphere was clear, a pilot flying at night at around 17,000 feet could detect their beams from a distance of 150 kilometers. The powerful aerial lighthouse on the right, serving the Paris-Algiers route and others, produced a combined light worth one billion candlepower, and it could be spotted 300 kilometers away in clear weather.
Above is a 1920's photograph of an electric carbon arc searchlight lighting up
the Paris airfield as aFrench Farman "Goliath" lands after a flight from London.
An old 1.2-meter (48-inch)-diameter mobile searchlight illustrated in the 1925
edition of L. Fournier's Bibliotheque des Merveilles (Library of Marvels)
The French used motorized light projectors similar to the one illustrated above to light up their runways, and Americans also used mobile searchlights to light up their airfields in the 1920's. However, according Sally Macready Wallace, while U. S. Army Air Service lieutenants Macready and Kelly were breaking the French endurance record (for non-stop flying) in October of 1922, Captain Ervin had ordered his men to "pull out the big searchlights" so they would be ready to turn on to illuminate the field if a night landing became necessary. Apparently, unlike the French and other U. S. airfields, the facilities at Rockwell Field (now North Island Naval Air Base) in San Diego, California provided only hand-drawn types of searchlights, like the General Electric aluminum version illustrated below:
An early twentieth-century aluminum version of General Electric's 36-inch hand
controlled high intensity searchlight mounted on a four wheeled truck for Army use
In 1923, similar searchlights, mounted on brackets to be lifted from their wheels, were being manufactured specifically to use as rotating airfield beacons. An edition of the Cleveland Sunday News-Leader included the illustration below and reported: "Hazards of 'Flying the Mail' at night on non-stop coast-to-coast flights will be lessened soon by five huge beacon lights, 36 inches in diameter and of 500,000,000 candlepower each, which will guide the way in the dark zone between Chicago and Cheyenne, Wyo. The aviators will fly in the daytime east of Chicago and west of Cheyenne."
Extracted from an article "Aces of the Air Mail" in the
September 1925 issue of Everybody's magazine
Locations of five airfield terminals on the night leg of the transcontinental air
mail route, each brandishing a 36-inch, 500,000,000 candlepower arc light beacon
A photograph in Everybody's magazine of night loading a plane for Cheyenne
at Fort Crook field in Omaha, on the transcontinental air mail route
Carbon arc searchlights of the type illustrated above were also used to spread their light over landing fields, and a 1925 article in Everybody's magazine aptly described the brilliant effect of these airport lights. "Through most seasons of the year the relay from Omaha to Cheyenne is covered at night, but the half-billion candle-power flood lights illuminate the terminal fields as brilliantly as the sun," wrote Samuel Taylor Moore. "Even those powerful lights are sometimes obscured by snow drifts by the fierce winds that sweep over the plains from the Rocky Mountains."
The BBT Company's modified lighthouse Fresnel-type lenses with 150 amp
carbon arc lights used for lighting up air mail landing fields in the 1920's
However, a few years later airfield illumination had moved out of searchlights into lighthouse lenses. With reference to the mobile carbon arc light on the right above, in a G.E. publication of 1928, with the booklet's title illustrated below, C. E. Weitz discussed the current type of airfield lighting by relating:
From a 1928 Bulletin LD-158 on Lighting Data for Airway and Airport Lighting,
published by the Edison Lamp Works of General Electric Company
"The present methods of lighting landing fields grew out of the early experience of the U. S. Army Air Corps in meeting the requirements for military operations. Army practice demanded flexibility and portable power apparatus using D. C. generator equipment in combination with a motor truck. For this service the 150-ampere arc with a modified type of BBT lighthouse lens, as shown above, was remarkably well adapted. The portable feature allowed the units to be moved about at will and located with respect to wind direction for favorable landing conditions.
A high intensity electric carbon arc airport light illuminating an early twentieth
-century flying field, from the 1926 Christmas issue of U.S. Air Services
"With the precedent of army practice, the high intensity arc system was naturally adopted for the first commercial fields. Since these first installations, considerable study has been made of lighting problems for commercial airport operations as contrasted to army requirements. The expense incident to the servicing and attendant of the arc, the operation from fixed locations, and the general demand for more field illumination has led to the development of other field floodlighting equipments which have distinct advantages over the arc equipment."
The General Electric Company had a vested interest in other forms of airport lighting, but still it was well known that
“The carbon arc has the greatest brightness per unit area of any artificial light source known, rivaling that of the sun, states a 1932 book titled National Projector Carbons, published by the National Carbon Company—a popular U. S. manufacturer of carbons for carbon arc lights. “It is not surprising, then, that it has been adapted to the projection of motion pictures, to the projection of stereopticon slides, to spot and flood lighting in theatres, to the lighting of photographer’s studios, to photo-engraving, to the large powerful searchlights used by the Army and Navy, and last, but not least, to the modified type of searchlights used to illuminate the Air Mail Fields being established throughout the country.”
A U.S. Air Services magazine advertisement in its December 1926 Christmas
issue for a high intensity Sperry floodlight (searchlight) for use at airfields
For readers interested in statistics, we are including the following map with its block of data. It is extracted from an undated "Bulletin LD-158" titled Lighting Data, issued by the Edison Lamp Works of the General Electric company. After considering a date in its text and comparing it with a map of U. S. airways as of December 31, 1927, we are certain this map and data apply to some time in 1928.
The use of carbon arc lights at the growing number of airports often lit up the way.
This page was last modified on Tuesday, January 19, 2016